Infectious feline viral rhinotracheitis is a specific, common and serious disease of cats caused by the feline herpesvirus known as feline viral rhinotracheitis (FVR) virus. Reports in the literature indicate that this disease is responsible for approximately half the clinical cases of feline respiratory infections. The virus infects the epithelial cells of the nose, pharynx, trachea and eye, causing epitheliolysis and necrosis. The ocular manifestations predominantly involve the conjunctiva; however ulcerative keratitis can develop. The virus is shed from the nose, eyes and mouth through the course of the clinical disease. FVR virus infections are often severe and the mortality may be significant, especially in young kittens. Abortion or generalized infection of newborn kittens may occur following infection of pregnant queens with the virus. The transmission of FVR virus to susceptible cats is generally by intranasal instillation, for example, by droplets expelled in sneezing or by contact (usually nose to nose). Resistance following recovery from natural or experimental infection is of short duration (1-3 months).
The causative virus of FVR was first isolated from infected cats by R. A. Crandell and F. D. Maurer, Proc. Soc. Exptl. Biol. and Med., 97, 487 (1958) and the name "feline viral rhinotracheitis" was first proposed for the disease by R. A. Crandell and E. W. Despeaux, Proc. Soc. Exptl. Biol. and Med., 101, 494 (1959). Since then, several reports have appeared in the literature which confirm the isolation of FVR virus from feline subjects in various parts of the world, which identify the virus as a feline member of the herpesvirus group, and which describe the transmission, epidemiology and histologic characteristics of the disease. For example, see J. L. Bittle et al., Amer. J. Vet. Res., 21, 547 (1960); R. A. Crandell et al., J.A.V.M.A., 138, 191 (1961); J. Ditchfield and I. Grinyer, Virology, 26 504 (1965); R. H. Johnson and R. G. Thomas, Vet. Rec., 79, 188 (1966); R. C. Povey, Vet Rec., 82, 335 (1969); T. E. Walton and J. H. Gillespie, Cornell Vet., 60, 232 (1970); Colloquium Report, J.A.V.M.A., 157, 2043 (1970); R. A. Crandell, J.A.V.M.A., 158, 922 (1971); and S. I. Bistner et al., J.A.V.M.A., 159, 1223 (1971). An excellent up to date review is provided by R. A. Crandell in the chapter entitled "Feline Viral Rhinotracheitis (FVR)" in the book "Advances in Veterinary Science and Comparative Medicine" , Volume 17, Edtd. by C. A. Brandly and C. E. Cornelius, pages 201-24, Academic Press, Inc., New York, 1973.
Although attempts to produce a feline viral rhinotracheitis virus vaccine have been reported, none have proven successful. Investigators in England [Povey & Johnson, J. Small Anim. Pract., 11, 490 (1970)] reported failure in attempts at vaccine prophylaxis with a live, non-attenuated FVR virus vaccine given intramuscularly. Although they obtained a degree of success with formalinized and beta-propiolactone inactivated FVR virus vaccines in experimental cats, such vaccines failed to significantly reduce the incidence of disease in feline colonies. To date, no effective vaccine is available for protecting cats against FVR virus.